1. Field
The embodiments generally relates to the technical field of mobile communication, and more particularly relates to a reception apparatus, path detection apparatus, method thereof, and computer product used in a Code Division Multiple Access (CDMA) system base station.
2. Description of the Related Art
In a CDMA mobile communication system, the transmission signal is encoded as error correcting code and data modulated, and is then spread by a spreading code sequence and transmitted wirelessly. As the transmission signal propagates through a broad-band wireless link to the receiving party the signal is affected by planimetrical features or buildings. At the receiving party the signal is despread, is divided into one or more multipath components, then these components are Rake combined. The Rake combined signal is data demodulated, the error correcting code is decoded, then the transmission signal is restored. The path timing, which is the time at which each of the one or more multipath components reaches a receiver, differs depending on the condition of the wireless link. Therefore, by performing path detection, the receiver must be able to maintain the most recent value of the path timing for the signal from the transmitter. Particularly, Base Transceiver Stations (BTS) which communicate with a large amount of User Equipment (UE), must perform such path detection with each of the user equipment. The calculation load of path detection is significant, so the path detector accounts for a relatively large portion of the reception part. Performing path detection to increase the update frequency (priority) of the user equipment to which a new communication channel is trying to be established is set forth in Japanese Laid-Open Patent Publication No. 2000-151558. Hereinafter, Base Transceiver Stations are also referred to as BTS and User Equipment is also referred to as UE.
In view of the prior art it would be advantageous to address the problem of moderating the update frequency of the path timing for each of the user equipment used when rake combining is performed at a CDMA system base station.